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FOC | Family List | FOC Vol. 13 | Begoniaceae

1. Begonia Linnaeus, Sp. Pl. 2: 1056. 1753.

秋海棠属 qiu hai tang shu

Perennial succulent herbs, rarely subshrubs. Stem erect, frequently rhizomatous, or plants tuberous and either acaulescent or shortly stemmed, rarely lianoid or climbing with adventitious roots, or stoloniferous. Leaves simple, rarely palmately compound, alternate or all basal; blade often oblique and asymmetric, rarely symmetric, margin often irregularly serrate and divided, occasionally entire, venation usually palmate; petiole long, weak; stipules membranous, usually deciduous. Flowers unisexual, plants monoecious, rarely dioecious, (1 or)2-4 to several, rarely numerous, in dichotomous cymes, sometimes in panicle, with pedicels and bracts. Staminate flower: tepals 2 or 4 and decussate, usually outer ones larger, inner ones smaller; stamens usually numerous; filaments free or connate at base; anthers 2-celled, apical or lateral; connectives extended at apex, sometimes apiculate. Pistillate flower: tepals 2-5(-10); pistil composed of 2-5(-7) carpels; ovary inferior, 1-3(-7)-loculed; placentae axile or parietal; styles 2 or 3(or more), free or fused at base, forked once or more; stigma turgid, spirally twisted-tortuous or U-shaped, capitate or reniform, setose-papillose. Capsule dry, sometimes berrylike, unequally or subequally 3-winged, rarely wingless and 3- or 4-horned; seeds very numerous, pale brown, oblong, minute, testa reticulate.

More than 1400 species: widely distributed in the tropical and subtropical regions of the world, with ca. 150 species in Africa, more than 600 species in Central and South America, and more than 600 species in Asia; 173 species (141 endemic) in China.

Begonia species in China are mostly distributed S of the Chang Jiang, particularly concentrated in SE Yunnan and SW Guangxi, with only a few extending into N China.

The authors learned of two additional, recently described species as this volume was going to press. Begonia guaniana H. Ma & H. Z. Li (Ann. Bot. Fenn. 43: 466. 2006) was described from NE Yunnan (Yanjin), where it grows on moist cliffs under bamboo forest at ca. 500 m. Its chromosome number is 2n = 24*. It resembles B. labordei, especially in its tuberous, stemless habit. Begonia coelocentroides Y. M. Shui & Z. D. Wei (Acta Phytotax. Sin. 45: 86. 2007) was described from W Yunnan (Yingjiang), where it grows on cliffs often in forests or near streams at ca. 1300 m, flowering in August and fruiting in October. It resembles B. oreodoxa in having parietal placentae at the upper part of the ovary, differing mainly in the female flowers with 5 tepals and the largest wing of the capsule being 20-22 mm and ligulate.

The records of Begonia balansana Gagnepain from Guangxi and Yunnan in FRPS (52(1): 212. 1999) are possibly errors and require confirmation. The second author has seen no specimens from China that would substantiate these records. This species is believed to be endemic to N Vietnam. See also Tebbitt (Edinburgh J. Bot. 60: 1-9. 2003).

It can be difficult to key out the sections of Begonia, because sectional distinctions rely heavily on the placentation structure, which is either unavailable on specimens or difficult to analyse (many Begonia specimens are poorly prepared). Information on sections to which Begonia species belong may be desirable to specialists, although it should be noted that there are disagreements about the placement of some species. Please refer to Y. M. Shui, C.-I Peng & C. Y. Wu, Synopsis of the Chinese species of Begonia (Begoniaceae), with a reappraisal of the sectional delimitation (Bot. Bull. Acad. Sin. 43: 313-327. 2002).

In China, all species are perennial herbs (rarely subshrubs). All species with basal tubers are described as deciduous, although living material is not available for all tuberous species. The aerial parts of the plants wilt in winter or in the dry season. Most species are monoecious with cymose, dichasial inflorescences. The inflorescences are usually protandrous (staminate flowers open before pistillate flowers) and gynaeandrous (staminate flowers basal and pistillate flowers distal).

Key 7

1 Leaf blade shallowly lobed (divided to ca. 1/3 of leaf length); lobes nearly as long as wide or distinctly longer than wide   (2)
+ Leaf blade unlobed or very shallowly divided; lobes usually wider than long   (11)
2 (1) Leaf blade with hairs longer than 2 mm   (3)
+ Leaf blade with hairs to 1 mm at most   (5)
3 (2) Rhizomes short, stout; abaxial wing of mature capsules broadly elliptic to orbicular, 2-3 cm   163 B. villifolia
+ Rhizomes well developed; abaxial wing of mature capsules triangular to ligulate, to 1.8 cm   (4)
4 (3) Leaves purple, with purplish, somewhat soft hairs.   128 B. purpureofolia
+ Leaves green, with red stiff hairs.   12 B. baviensis
5 (2) Leaf blade abaxially hirsute; styles 3; ovary 3-loculed.   95 B. malipoensis
+ Leaf blade not hirsute; styles 2; ovary 2-loculed   (6)
6 (5) Leaves villous or tomentose on petiole and abaxial surface; ovary hairy   (7)
+ Leaves neither villous nor tomentose; ovary glabrous   (9)
7 (6) Leaves villous on petiole and abaxial surface.   149 B. smithiana
+ Leaves appressed tomentose on petiole and abaxial surface   (8)
8 (7) Tepals yellowish.   52 B. flaviflora
+ Tepals white to pink.   111 B. palmata
9 (6) Leaf blade adaxially glabrous or subglabrous, not puberulous.   54 B. formosana
+ Leaf blade puberulous   (10)
10 (9) Leaves rugulose, lobes truncate.   158 B. truncatiloba
+ Leaves not rugulose, lobes triangular.   45 B. edulis
11 (1) Leaf blade symmetric or nearly so; tepals pink to brownish red.   126 B. psilophylla
+ Leaf blade distinctly asymmetric; tepals white to pink   (12)
12 (11) Leaf blade thin, membranous when dried; styles 3; ovary 3-loculed   (13)
+ Leaf blade not membranous; styles 2 or 3; ovary 2- or 3-loculed   (17)
13 (12) Inflorescences both terminal and axillary.   72 B. hymenocarpa
+ Inflorescences axillary   (14)
14 (13) Plant with a short, stout rhizome at base; leaf blade 7-12 × 4.5-9 cm   (15)
+ Plant not rhizomatous, prostrate or trailing at base; leaf blade 4-9 × 3-5 cm   (16)
15 (14) Plant ca. 60 cm tall; leaf blade oblong-ovate or oblong, 9-10 × 4.5-9 cm.   27 B. clavicaulis
+ Plant 26-35(-39) cm tall; leaf blade triangular-ovate, 7-12 × 4.5-7 cm.   165 B. wenshanensis
16 (14) Leaf blade unlobed, margin sharply denticulate; tepals hairy.   102 B. morifolia
+ Leaf blade very shallowly lobed, margin irregularly denticulate; tepals glabrous.   4 B. alveolata
17 (12) Female flower axillary, solitary; terminal inflorescence staminate; plant with prostrate or decumbent stem, with distinct internodes.   151 B. sublongipes
+ Flowers of both sexes mixed in the inflorescence; plant rhizomatous, with indistinct internodes and/or erect with distinct internodes   (18)
18 (17) Rhizome absent.   41 B. discrepans
+ Rhizome present   (19)
19 (18) Plant to 13 cm tall; rhizome slender.   53 B. fordii
+ Plant much taller; rhizome stout   (20)
20 (19) Leaf blade adaxially densely hairy   (21)
+ Leaf blade adaxially glabrous to sparsely hairy   (24)
21 (20) Rhizome short, stout; leaves only on aerial stem; leaf blade puberulous.   17 B. cathayana
+ Rhizome elongate; leaves on rhizome and aerial stem; leaf blade not puberulous   (22)
22 (21) Staminate flowers usually prematurely dropping in bud; pollen abortive.   105 B. nantoensis
+ Staminate flowers opening normally; pollen fertile   (23)
23 (22) Leaf blade 6-7 × 4-5 cm; stipules and bracts ciliate.   121 B. polytricha
+ Leaf blade 7-16(-25) × 5-9(-14) cm; stipules and bracts entire.   119 B. pinglinensis
24 (20) Leaf abaxial surface and petiole densely puberulous; tepals abaxially puberulous.   43 B. dryadis
+ Leaf and tepals not puberulous   (25)
25 (24) Leaf blade basally cuneate to rounded, abaxially tomentose.   66 B. hekouensis
+ Leaf blade basally cordate, not tomentose   (26)
26 (25) Female flowers with 2 bracteoles; bracts serrate; abaxial wing of capsule to 5 mm.   157 B. tengchiana
+ Female flowers without bracteoles; bracts entire; abaxial wing of capsule much longer   (27)
27 (26) Rhizome elongate; leaves usually present on rhizomes at anthesis   (28)
+ Rhizome short, stout; leaves not seen on rhizomes at anthesis   (30)
28 (27) Abaxial wing of capsule triangular, 7-16 mm.   54 B. formosana
+ Abaxial wing of capsule orbicular, 18-26 mm   (29)
29 (28) Aerial stem 0-8(-15) cm; leaf subleathery.   14 B. bouffordii
+ Aerial stem 40-95 cm; leaf herbaceous.   23 B. chitoensis
30 (27) Leaves abaxially sanguineous; anthers 1.9-2.2 mm; styles 3; ovary 3-loculed.   91 B. lukuana
+ Leaves green; anthers 2.4-3.2 mm; styles 2 or 3; ovary 2- or 3-loculed   (31)
31 (30) Styles 3; ovary 3-loculed; anthers 2.9-3.2 mm.   24 B. chuyunshanensis
+ Styles 2; ovary 2-loculed; anthers 2.4-2.9 mm.   167 B. wutaiana

List of Keys

  • List of lower taxa


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